GENERATION AND CYCLOADDITION REACTIONS OF SUBSTITUTED 2-NITRO-1,3-DIENES

4-Acyloxy-2-substituted-3-nitro-1-butenes have been utilized as conven ient precursors of the corresponding 2-nitro-3-substituted-1,3-butadie nes which could be easily generated in situ by heating or by treatment with sodium acetate and trapped by suitable partners such as methyl a crylate, cyclopentadiene or ethyl vinyl ether. The expected cycloadduc ts are regiochemically formed by reaction with methyl acrylate, while the initially formed adducts with cyclopentadiene underwent thermal Co pe or hetero-Cope rearrangements leading to the formation of nitro-sub stituted bicyclic compounds. The thermal rearrangement of the oxazine- N-oxides resulting through hetero Diels-Alder reaction with ethyl viny l ether as cycloaddition partner led to the formation of 1,2-oxazole-3 -propionaldehydes. The wide variety of highly functionalized carbocycl ic and heterocyclic compounds generated through the use of these multi -coupling reagents provided useful synthons for the construction of si mple and complex natural compounds. Copyright (C) 1996 Elsevier Scienc e Ltd